Hong Kong's air quality continues to improve, bringing over 50 per cent reduction in long-term health risks
The Environmental Protection Department (EPD) announced today (March 21) an overview of Hong Kong's air quality in 2024.
Hong Kong's overall air quality in 2024 remained good andbroadly complied with Hong Kong's Air Quality Objectives. Owing to the efforts of the Hong Kong Special Administrative Region Government over the years, Hong Kong's air quality has continued to improve over the past 20 years, resulting in over a 50 per cent reduction in long-term health risks.
From 2004 to 2024, the annual average concentrations of respirable suspended particulates (PM10), fine suspended particulates (PM2.5), nitrogen dioxide (NO2) and sulphur dioxide (SO2) in the ambient air have reduced by 45 per cent to 88 per cent, whereas the annual average concentrations of these pollutants at the roadside have reduced by 36 per cent to 88 per cent. The annual average concentration of ozone (O3) has also gradually turned steady in the past few years (see Annex 1 for details). The number of hours of reduced visibility has greatly reduced by 82 per cent from its level in 2004 (Annex 2).
The EPD launched the Air Quality Health Index (AQHI) in 2014 to provide the public with daily updates on short-term health risks of air pollution, enabling the individuals to take necessary precautions to safeguard their health. In 2024, the percentage of hourly AQHI readings below 7 (i.e. within the "low" or "moderate" health risk categories) recorded by general and roadside monitoring stations improved from 96.1 per cent and 92.1 per cent when the index was first launched in 2014 to 98.7 per cent and 98.9 per cent, respectively.
Despite the increase in regional ozone levels, the significant improvement in Hong Kong's air quality has resulted in a continuous reduction in the associated long-term health risks. From 2004 to 2024, the improvement in air quality has led to over a 50 per cent reduction in long-term health risks (Annex 3).
Making reference to health risk data from hospital admissions associated with air pollutants over the past decade, the EPD will update the relevant risk factors assigned to relevant air pollutants. The EPD will also update the compilation methods of AQHI with reference to the latest guideline levels for air pollutants as set out in the latest air quality guidelines published by the World Health Organization, thereby providing more accurate information and warning forecast. The updated AQHI will come into effect on March 22, 2025. Detailed information on the updates will be made available to the public via the dedicated AQHI websitewww.aqhi.gov.hk/en/index.html.
An EPD spokesman said, "With the Government's continued promotion and implementation of the comprehensive air quality improvement measures put forth in the Hong Kong Roadmap on Popularisation of Electric Vehicles, the Clean Air Plan for Hong Kong 2035 and Hong Kong's Climate Action Plan 2050 announced in 2021, and the Green Transformation Roadmap of Public Buses and Taxis announced in 2024, including the promotion of electric vehicles, green transport and net-zero electricity generation, the overall air quality in Hong Kong will improve continuously."
Update on chikungunya fever
The Centre for Health Protection (CHP) of the Department of Health announced that, as of 5pm today (January 4), no new cases of chikungunya fever (CF) had been recorded.
Latest surveillance data
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Hong Kong has recorded a total of 82 confirmed CF cases last year. Among them, 11 were local cases, and the rest were imported cases.
Since the beginning of 2025, and as of December 10, 2025, a total of 502 264 CF cases and 186 CF-related deaths have been reported in over 40 countries/territories. Cases have been reported in the Americas, Africa, Asia, and Europe. Although the northern hemisphere has entered the winter season, temperatures in subtropical and some temperate regions remain elevated due to climate change, creating favourable conditions for mosquito breeding. In addition, CF outbreaks continue to occur in many countries worldwide. The risk of imported cases persists. Members of the public should check the situation of the destinations before travelling abroad, especially when travelling to Southeast Asian countries.
Government's comprehensive follow-up actions
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Given that some local cases of CF have visited the Tsing Yi Nature Trails or the surrounding area in November last year, the trails are currently closed until further notice. Relevant government departments continue to conduct large-scale mosquito control and prevention efforts along the trails, and the CHP appeals to the public not to enter the area in order to reduce the risk of contracting CF and to avoid exposure to chemicals or interfering with the mosquito control operations. Since the confirmation on December 10, 2025, of a case involving a person who had visited the Tsing Yi Nature Trails on November 30, 2025, no further local cases have been recorded to date. The CHP continues to urge individuals who have recently hiked along the Tsing Yi Nature Trails to seek medical attention as soon as possible if they develop relevant symptoms and to call the enquiry hotline (Tel: 2125 2373), which operates from 9am to 6pm.
The Food and Environmental Hygiene Department (FEHD) has been continuously conducting intensive fogging operations to eliminate adult mosquitoes along the Tsing Yi Nature Trails and the surrounding area. At suitable locations, large ultra-low volume foggers have been deployed, and a robot dog is being put on trial to enhance operational effectiveness. The FEHD has also set up new mosquito trapping devices, cleared discarded containers and garbage that could cause stagnant water, and applied larvicide oil or larvicides in areas with stagnant water that cannot be removed immediately. The FEHD has been collaborating with the Kwai Tsing District Office, the Lands Department and the Drainage Services Department to strengthen efforts in eliminating potential mosquito breeding sites along the Tsing Yi Nature Trails. Pamphlets have been distributed to hikers in the area, urging citizens to be vigilant against mosquito infestations and take personal protective measures. The FEHD has also held meetings of the interdepartmental task forces on anti-mosquito work across districts to discuss the latest developments regarding the situation and plan accordingly to co-ordinate relevant departments and stakeholders in strengthening mosquito prevention and control measures in areas under their purview.
Continuously strengthening prevention and control
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The FEHD and relevant departments have comprehensively enhanced the mosquito control operations in Hong Kong since July last year, and this has continued. Among these, the FEHD has conducted vector investigations and targeted mosquito control operations against the imported and local cases. In light of the local case, the FEHD has immediately conducted follow-up actions, including:
carrying out intensive fogging in scrubby areas within a 250-metre radius of the relevant locations to kill adult mosquitoes;
carrying out inspections of the locations, removing stagnant water, applying insecticides and disposing of abandoned water containers every week with a view to preventing mosquito breeding; and
enhancing public education efforts through organising health talks, setting up mobile education stations, and distributing publicity leaflets.
The abovementioned measures will be continued. Furthermore, the Government will further enhance the mosquito control efforts in addition to the existing measures.
Preventive measures to be taken by the public
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Members of the public should use DEET-containing insect repellents or other effective active ingredients properly to prevent mosquito bites, but the following precautions should be taken when using them:
read the label instructions carefully first;
apply right before entering an area with a risk of mosquito bites;
apply on exposed skin and clothing;
use DEET of up to 30 per cent for pregnant women and up to 10 per cent for children (for children who travel to countries or areas where mosquito-borne diseases are endemic or epidemic and where exposure is likely, those aged 2 months or above can use DEET-containing insect repellents with a DEET concentration of up to 30 per cent);
apply sunscreen first, then insect repellent;
reapply only when needed and follow the instructions; and
in addition to DEET, there are other insect repellents available on the market containing different active ingredients, such as IR3535 and picaridin. When using any insect repellent, the public should follow the usage instructions and precautions on the product label.
The FEHD also appeals to members of the public to continue to stay alert and work together to carry out mosquito prevention and control measures early, including inspecting their homes and surroundings to remove potential breeding grounds, changing water in vases and scrubbing their inner surfaces, removing water in saucers under potted plants at least once a week, and properly disposing of containers such as empty cans and lunch boxes. The FEHD also advises members of the public and property management agencies to keep drains free of blockage and level all defective ground surfaces to prevent the accumulation of water. They should also scrub all drains and surface sewers with an alkaline detergent at least once a week to remove any mosquito eggs.
The public should call 1823 in case of mosquito problems, and may visit the following pages for more information: the CF page of theCHPand theTravel Health Service, the latestTravel Health News,tips for using insect repellents, and the CHPFacebook Page,Instagram AccountandYouTube Channel, and also theMosquito Prevention and Control dedicated pageof the FEHD.
Source: AI-found images
